JPS6036046B2 - Manufacturing method of enameled electric wire using both electrodeposition coating and powder coating - Google Patents

Description

[Detailed Description of the Invention] The present invention produces an enameled electric wire using a combination of lightning coating and powder coating, or a combination of electrodeposition coating and electrostatic dynamic bond coating, which is a type of powder coating. It is about the method.

The development of heat-resistant resins such as epoxy resins and polyesterimide resins as powder coatings has enabled powder coatings to move from anti-corrosion and decorative applications to electrical insulation applications, such as insulated busbars for switchboards. As is well known, it has been put to practical use in applications such as armatures and commutators of large DC machines, coil end parts of small rotating machines, and sealing of electronic components.

Recently, attempts have been made to apply this to insulation coatings on enamelled wires, but this has not yet been put to practical use. The main reason for this is that the dielectric strength of the insulating film obtained by powder coating is at most 20 to 3 F/m, which is 1/5 to 1/5 of the dielectric strength of the insulating film of enamelled wires coated with ordinary bond coating. This is because only a value of /8 can be obtained. In the first place, the insulating film of powder coating is obtained by the mutual fusion of powder particles by heating, but heating alone does not have enough melting and fluidizing effects of the powder particles, and although a film with no defects is formed at first glance, there are slight defects. Visually, an insulating film with many fine voids is formed. Therefore, it is not suitable for coating enameled wires which require a thin film and high dielectric strength, and in reality, enameled wires using powder coating have not been put into practical use. On the other hand, enameled electric wires using electrodeposition coating have been on the market for about five years, but they are limited to those with an enamel coating thickness of 50 to 60 mm or less. The reason why the film thickness is limited is that the manufacturing method of enamelled wires using open coating is different from the conventional bond coating, which requires multiple coatings and multiple baking, and the method of manufacturing enamelled wires is that it is obtained by one coating and one baking. This can be mentioned. In other words, the existing manufacturing method for exposed enamel electric wires uses a water-dispersed varnish, and as shown in Japanese Patent Publication No. 45-31555, an organic solvent is applied before the baking process after fogging. A processing step is an essential condition. When the lightning deposit layer that becomes the enamel film becomes thicker, the moisture in the lightning deposit layer or the organic solvent used in the post-processing process scatters during baking, making it difficult to form foams and pins under normal baking conditions for thin films. Film defects such as holes occur. This phenomenon becomes extreme as the thickness of the film increases, and under normal drawing conditions, the thickness of the electrodeposited enamel film is naturally limited to 50 to 60 mm. The present invention compensates for the drawbacks of insulating coatings obtained by dew coating and powder coating. Specifically, after lightning coating is applied, powder coating or electrostatic coating, which is a type of powder coating, is applied. By applying dipping coating (hereinafter referred to as electrostatic current dipping coating) to form an enamel wire coating, it is possible to obtain a coating of 60mm, which is difficult to obtain with the open coating method.
100~, which is impossible to obtain with powder coating method.
A method of coating an enameled electric wire with a dielectric strength of 20 μm/wm is provided.

In other words, by applying powder coating by powder coating or electrostatic immersion coating during heating after the post-treatment process, the organic solvent applied in the post-treatment process causes the powder coating particles to swell, and the air remaining inside By forcing the powder to the outside, it not only accelerates the melting of the powder coating, lowers the minimum film formation temperature of powder coating, and facilitates film formation, but also allows microscopically minute voids to be completely present. A complete enameled wire coating is formed. Hereinafter, the present invention will be explained based on FIGS. 1 and 2 of the accompanying drawings. Figure 1 shows the main components of a horizontal wire drawing machine used to carry out the method of the present invention using powder coating.
The water-dispersed varnish particles deposited on the conductive wire 1 swell and melt in the post-treatment tank 5 containing a film forming aid 4, which is an organic solvent. wear it.

The preheating furnace 6 serves to promote the formation of a film from the haze deposited layer and at the same time to generate heat from the conductor 1, which is the object to be powder coated. The heated conducting wire 1 is powder-coated in a swinging coating tank 8 containing a powder coating 7, and particles of the powder coating coated on the electrodeposited layer remain in the dew-deposited layer. The coating is swollen by the film-forming aid used to form a smooth powder coating without defects such as pinholes, unlike powder coatings obtained only by powder coating. Note that the step of passing it through a preheating furnace may be omitted. Thereafter, the electrodeposited layer and the powder coating film are heated and hardened in a heating furnace 9 to obtain a complete enameled electric wire. Second
The figure shows the main components of a rigid wire drawing machine used to carry out the method of the present invention using the electrostatic dipping method. Electrodeposition is performed in the tank 13.

The counter electrode 14 is located inside the mounting tank 13 and is supplied with current from a DC power source 15 . Next, the conductive wire 11 is placed in a post-treatment device 17 containing a film-forming aid 16, which is an organic solvent, so that the water-dispersed varnish particles deposited on the conductive wire 11 swell and adhere thereto.
The film forming aid 16 is supplied from an inlet 71 of the after-treatment device 17, taken out from an outlet 72, and circulated. The conductor 11 coated with the film-forming agent is coated in an electrostatic dipping bath 19 containing charged powder coating. The powder coating 18 has an air intake port 91 and a porous ceramic plate 2.
0, it is oscillated by ionized air sent through the charging electrode 21 and is negatively charged. The charged particles are discharged onto the lightning deposited layer, uniformly coated, and swollen by the film-forming agent remaining in the haze deposited layer. Subsequently, in the preheating furnace 23, the powder particles on the open deposition layer are heated. The coating is uniform, and unlike coatings obtained by electrostatic immersion alone, a smooth coating is formed without defects such as pinholes. Thereafter, the lightning deposition layer and the powder coating film are heated and hardened in a baking furnace 24 to obtain a complete enameled electric wire. As the water-dispersed varnish used here, ordinary electrodeposition paint for enameled electric wires can be applied without any problem.

Examples include water-dispersible varnishes such as acrylic-epoxy, polyester, eboxyester, polyesterimide, polyesteramideimide, and polyimide. The film-forming agent is selected as appropriate depending on the serigraphy paint or powder paint used, and includes hydrophilic or partially aqueous organic solvents, such as ethyl cellosolve, butyl cellosolve, dimethylamide, dimethylacetamide, N,N dimethylformamide. (hereinafter abbreviated as DM) and N-methyl-2-pyrrolidone are used as appropriate. As the powder coating, powder coatings such as epoxy resin and polyesterimide resin are preferably used for electrical insulation.

A detailed explanation will be given below with reference to comparative examples and examples.

Comparative Example 1 A bare copper wire (20) running at a speed of h per minute in acrylic-epoxy water-dispersed varnish V-550-21 (manufactured by Ryoden Kasei), which is a typical varnish for electrodeposited enameled electric wires, The electrode facing this was immersed, and the bare copper wire was used as an anode, and a DC voltage of 15
Electrodeposited layer by applying V for 2 seconds (finished film thickness 75 mm)
DM in a post-treatment tank with a length of about 50 mm.
After being immersed in F for 6 seconds, it was transported through a subheating furnace with a maximum internal temperature of about 250°C and an additional heating furnace with a maximum internal temperature of 36,000°C for 3 inspections, and electrodeposition coating was applied. produced enamel electric wire.

Its characteristics are shown in Table 1. Comparative Example 2 A bare copper wire (20) running at 5 m/min in acrylic-epoxy water-dispersed varnish V-550-21 (manufactured by Ryoden Kasei), which is a typical varnish for exposed enameled electric wires, and this The electrode facing the electrode is immersed, and a DC voltage of 15
V was applied for 2 seconds to form an exposed deposited layer (finished film thickness 75〃m).
), and then DM in a post-processing device for about 50 skins.
After 6 seconds of exposure to F steam, the furnace temperature was between 230 and 280℃.
The temperature inside the heating furnace for child heat is about 00 and the temperature inside the furnace is 320 to 390.
An enameled electric wire was produced by running it with 3-machi sand in an o0 sintering heating furnace and applying an open coating.

Its characteristics are shown in Table 1. Comparative example 3 15 by preheating furnace
Powder paint (VEP46- manufactured by Ryoden Kasei Co., Ltd.
7) was applied onto the bare copper wire, and then passed through a 34,000 sintering furnace for about 30 seconds to produce an enameled electric wire.

Its characteristics are shown in Table 1. Comparative Example 4 Epoxy-based powder paint (VEP46-7 manufactured by Ryoden Kasei Co., Ltd.) was charged with an electrostatic dipping device that generates a high voltage of DC4 and V while running a degreased bare copper wire at a speed of 5 m/min. ) was coated on the copper wire, passed through a 36,000 mm sintering furnace for about 3 inkstone steps, and then electrostatically immersed to form an insulating coating of 80 mm to produce an enameled electric wire.

Its characteristics are shown in Table 1. Example 1 A bare copper wire (20) running at 5 m/min was coated with acrylic-epoxy water-dispersed varnish V-550-21 (manufactured by Ryoden Kasei), which is a typical varnish for dew-applied enamel electric wires. The opposing electrodes were immersed, a bare copper wire was used as an anode, and a direct current voltage of 6 VI seconds was applied to form a lightning deposit layer, and then immersed for 6 seconds in ethyl cellosolve in a post-treatment tank with a length of about 50 skins. ,
15 in a heating furnace for child heat whose maximum temperature inside the furnace is about 25,000 ℃.
Electrodeposition coated copper wire is heated for a few seconds, and before the copper wire has completely cooled down, powder coating (VEP46 manufactured by Ryoden Kasei Co., Ltd.) is applied using the rocking coating method.
17) was applied on the lightning coating according to Comparative Example 3.

After that, it was passed through a heating furnace for about 3 nights to form an insulating film of 73 mounds.
Enamelled electric wire was produced. Its characteristics are shown in Table 1. Example 2 Following Comparative Example 1, a bare copper wire (second wire) was used as an anode and a DC voltage of 6VI seconds was applied to form an electrodeposited layer, and then placed in DMF in a post-treatment tank with a length of about 25 cm for 3 seconds. After being immersed, the electrodeposited copper wire is heated in a heating chamber with a maximum internal temperature of about 25,000 ℃ for 19 stages, and before the copper wire has completely cooled down, it is coated with trimethic anhydride, A polyesterimide powder coating consisting of diamenodiphenyl meth, polyethylene terephthalate, and glycerin was applied on the lightning coating in accordance with Comparative Example 3, and then passed through a 400 to 43,000 furnace with approximately 300 kg of actual sand. An enamil electric wire with an insulation coating of 71 m thick was manufactured.

Its characteristics are shown in Table 1. Example 3 Following Comparative Example 2, a bare copper wire (20) was used as an anode and a direct current voltage of 6VI seconds was applied to form an electrodeposited layer, and then an electrodeposited layer was formed using ethyl cellosolve in a post-processing device with a length of approximately 50 cm.
After exposure for seconds, electrostatic dipping was applied using an epoxy powder coating (VEP46-7 manufactured by Ryoden Kasei Co., Ltd.) according to Comparative Example 4, and heating for child heating was performed at a furnace temperature of 230 to 28,000. An enameled electric wire with an insulating coating of 72 meters was manufactured by running three pieces of inkstone sand inside the furnace and inside the sintering heating furnace where the temperature inside the furnace was 320 to 39,000.

Its characteristics are shown in Table 1. Example 4 Following Comparative Example 2, a bare copper wire (2 or so) was used as an anode, a direct current voltage was applied for 6VI seconds to form an exposed deposited layer, and then a DMF in a post-processing device with a length of about 50 cm was applied. After exposure for 6 seconds to Comparative Example 4, trimellitic anhydride, diaminodiphenylmethane, polyethylene terephthalate,
Electrostatic galvanic coating was applied using polyesterimide powder consisting of B-hydroxyethyl isocyanurate, and the temperature inside the furnace was 230 to 28,000 for preheating, and the inside of the furnace was at a temperature of 40,000 yen.
Enamel electric wires with an insulation coating of 70 qo were manufactured by running three pieces of sand in a grading furnace of 0 to 430 qo.

Its characteristics are shown in Table 1. Table 1 According to the present invention, thick-film enameled electric wires for thick wires (including flat wires) can be manufactured industrially by performing powder coating or electrostatic immersion coating after coating as shown in Table 1. It became.

Moreover, the present invention is more advantageous because it is suitable for rectangular wires.

That is, in the mist coating method, the electric field is concentrated at the corner portions and edge portions, resulting in a thicker wall than the flat portion, making it difficult to obtain a uniform thickness. On the other hand, powder coating provides poor coverage at corners and tends to be much thinner than flat areas. By using a haze coating method and a powder coating method or an electrostatic dipping method in combination as in the present invention, the drawbacks of both methods can be compensated for in covering corners and edges.
This results in a desirable state as an enamel insulation coating for flat wires.
The ratio of the haze-deposited coating to the powder coating should be determined depending on the purpose of use. If the wall is thin and high dielectric breakdown strength per unit thickness is required, the electrodeposited coating should be as thick as possible. If the entire insulating coating is required to be thick, it is more convenient to mainly form the powder coating.

[Brief explanation of the drawing]

1 and 2 are schematic illustrations of the apparatus used to carry out the method of the invention. 1, 11... Conductor wire, 2, 12... Electrodeposition liquid, 3, 13... Haze deposition tank, 4, 16... Film forming aid,
5, 17... Post-treatment tank, 6, 23...
Heating furnace for child heating, 7... Powder coating, 8... Rocking coating tank, 9, 24... Heating furnace, 14...
Electrode, 15... DC power supply, 18... Charged powder coating, 19... Electrostatic current immersion coating tank, 20...
... Porous ceramic plate, 21 ... Charged electrode, 22.
...High voltage power supply. groove l diagram purple 2 diagram

Claims (1)

[Claims] 1. By applying powder coating after electrodeposition coating, the film forming aid used in the post-treatment process of electrodeposition acts on the powder coating, creating an insulating coating for thick wires and thick walls. A method for manufacturing an enameled electric wire using both electrodeposition coating and powder coating, which is characterized by making it easy to shape. 2. The method for manufacturing an enameled electric wire according to claim 1, wherein the powder coating is electrostatic dynamic dipping coating. 3. The method for producing an enameled electric wire according to claim 1 or 2, wherein the electrodeposition liquid used in the electrodeposition coating is an acrylic epoxy water-dispersed varnish. 4. The method for producing an enameled electric wire according to claim 1 or 2, wherein the film forming aid used in the post-treatment step of electrodeposition coating is ethyl cellosolve. 5 The film forming aid used in the post-treatment process of electrodeposition coating is N,
The method for producing an enameled electric wire according to claim 1 or 2, wherein N' dimethylformamide is used. 6. The method for producing an enameled electric wire according to claim 1 or 2, using epoxy resin powder as the powder coating. 7. The method for manufacturing an enameled electric wire according to claim 1 or 2, using polyesterimide resin powder as the powder coating.